Touch-sensing liquid crystal panel and fabrication method thereof

ABSTRACT

A touch-sensing liquid crystal panel and a fabrication method thereof are provided. The touch-sensing liquid crystal panel includes a color filter substrate and a transistor substrate. In the fabrication method, at first, a first glass substrate is provided. Thereafter, a sensing matrix is formed on a first surface of the first glass substrate at a baking temperature. The sensing matrix is formed from indium tin oxide (ITO), and a sheet resistance of the sensing matrix is equal to or less than 30 ohm/square. Then, color filters and a common electrode are disposed on a second surface of the first glass substrate to form a color filter substrate, wherein the second surface is opposite to the first surface. Thereafter, the transistor substrate is provided and combined with the color filter substrate. Thereafter, a slimming process is performed to slim a second glass substrate of the transistor substrate.

RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 14/187,312, filed on Feb. 23, 2014, which claims priority to ChineseApplication Serial Number 201310251795.9, filed Jun. 24, 2013. Theentire disclosures of all the above applications are hereby incorporatedby reference herein.

BACKGROUND

1. Field of Invention

The present invention relates to a touch-sensing liquid crystal paneland a fabrication method thereof. More particularly, the presentinvention relates to a touch-sensing liquid crystal panel having atouch-sensing matrix using On Cell technology and a fabrication methodthereof.

2. Description of Related Art

In recent years, thin and light flat panel displays become populardisplays used in various electronics. In order to enable informationproducts to achieve the objects of convenient usage, concise appearance,and multiple functions, many information products use touch panels asinput devices instead of traditional keyboards, mice, etc.

With rapid development flat display and touch panel technologies, someelectronic products combine the touch panel with a display panel to forma touch-sensing display panel, so as to provide users with a greaterviewable screen area and more convenient operation modes under thecondition of limited volumes. Because the touch-sensing display panelhas the display function of the display panel and convenience of inputoperation of the touch panel, the touch-sensing display panel hasgradually become an important component applied in many electronicproducts such as a handheld PC, a personal digital assistance (PDA), ora smart phone.

The operation principle of the touch panel is based on that, when aconductor object (such as a finger) touches a touch-sensing matrix ofthe touch panel, a electrical property (such as electrical resistance orcapacitance) of the touch-sensing matrix is changed accordingly toresult in a change of a bias voltage applied on the touch-sensingmatrix. The change of the electrical properties is converted to acontrol signal outputted to an external control circuit board, and thena processor performs data calculation in accordance with the controlsignal to obtain a result. Thereafter, the external control circuitboard outputs a display signal to the display panel, and an image ispresented to users through the display panel.

In the current various technologies of touch panels, On Cell technologyis one of the most popular technologies, because the On Cell technologyhas advantages of low cost and convenience for assembling. In the OnCell technology, a sheet resistance of the touch-sensing matrix affectsthe performance of touch-sensing operation. For example, if atouch-sensing matrix has a greater sheet resistance, a touch-sensingdriver circuit of the touch-sensing matrix needs more power to performthe touch-sensing operation.

Therefore, there is a need to provide touch-sensing liquid crystal paneland a fabrication method thereof having a sensing matrix with a lowerelectrical resistance.

SUMMARY

Therefore, an aspect of the present invention provides a touch-sensingliquid crystal panel and a fabrication method thereof. The fabricationmethod uses high temperature baking technology to form a sensing matrixwith lower electrical resistance to provide the touch-sensing liquidcrystal panel having better touch-sensing performance.

According to an embodiment of the present invention, the touch-sensingliquid crystal panel includes a color filter substrate, a transistorsubstrate and a liquid crystal layer. The color filter substrateincludes a first glass substrate, a sensing matrix, color filters and acommon electrode layer. The first glass substrate has a first surfaceand a second surface, wherein the first surface is opposite to thesecond surface. The sensing matrix is disposed on the first surface ofthe first glass substrate, wherein the sensing matrix is formed fromindium tin oxide (ITO), and the sensing matrix has a sheet resistancesmaller than or equal to 30 ohm/square. The color filters are disposedon the second surface of the first glass substrate. The common electrodelayer is disposed on the color filters. The transistor substrateincludes a second glass substrate and a pixel layer. The second glasssubstrate is treated by a slimming process and has a thickness smallerthan 0.2 mm. The pixel layer is disposed on the second glass substrate,wherein the pixel layer includes pixel units, and each of the pixelunits includes a switching transistor and a pixel electrode. The liquidcrystal layer is disposed between the color filter substrate and thetransistor substrate.

According to another embodiment of the present invention, in thefabrication method of the e touch-sensing liquid crystal panel, atfirst, a color filter substrate is fabricated. In the operation forfabricating the color filter substrate, at first, a first glasssubstrate is provided, wherein the first glass substrate has a firstsurface and a second surface, and the first surface is opposite to thesecond surface. Thereafter, a sensing-matrix-forming step is performedto form a sensing matrix on the first surface of the first glasssubstrate at a predetermined process temperature, wherein the sensinglayer is formed from indium tin oxide and a sheet resistance of thesensing layer is smaller than or equal to 30 ohm/square. Then, filtersare formed on the second surface of the first glass substrate.Thereafter, a common electrode layer is formed on the color filters toform the color filter substrate. After the step for fabricating thecolor filter substrate, a transistor substrate is provided. Thetransistor substrate includes a second glass substrate and a pixellayer. The pixel layer is formed on the second glass substrate, whereinthe pixel layer includes pixel units, and each of the pixel unitsincludes a switching transistor and a pixel electrode. Then, the colorfilter substrate is combined with the transistor substrate and a liquidcrystal layer is formed between the color filter substrate and thetransistor substrate to form a liquid crystal panel. Thereafter, aslimming process is performed on the liquid crystal panel to slim thesecond glass substrate of the liquid crystal panel.

It can be understood from the above descriptions that the fabricationmethod of the touch-sensing liquid crystal panel forms a sensing matrixwith a sheet resistance equal to or smaller than 30 ohm/square, so as toprovide the touch-sensing liquid crystal panel having better performanceon touch-sensing. In addition, one side of the touch-sensing liquidcrystal panel is slimed to enable the touch-sensing liquid crystal panelto be thinner and lighter.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to make the foregoing as well as other aspects, features,advantages, and embodiments of the present invention more apparent, theaccompanying drawings are described as follows:

FIG. 1 is a flow chart showing a fabrication method of a touch-sensingliquid crystal panel in accordance with an embodiment of the presentinvention;

FIGS. 2a-2f are cross-sectional views of the touch-sensing liquidcrystal panel corresponding to the steps of the fabrication method inaccordance with an embodiment of the present invention;

FIG. 3 is a flow chart showing a fabrication method of a touch-sensingliquid crystal panel in accordance with another embodiment of thepresent invention;

FIGS. 4a and 4b are cross-sectional views of the touch-sensing liquidcrystal panel corresponding to the encapsulating steps of thefabrication method in accordance with an embodiment of the presentinvention; and

FIG. 5 is a structure diagram showing a pattern of the sensing matrix inaccordance with an embodiment of the present invention.

DETAILED DESCRIPTION

Reference will now be made in detail to the present preferredembodiments of the invention, examples of which are illustrated in theaccompanying drawings. Wherever possible, the same reference amounts areused in the drawings and the description to refer to the same or likeparts.

Referring to FIG. 1 and FIGS. 2a -2 f, FIG. 1 is a flow chart showing afabrication method 100 of a touch-sensing liquid crystal panel inaccordance with an embodiment of the present invention, and FIGS. 2a-2fare cross-sectional views of the touch-sensing liquid crystal panelcorresponding to the steps of the fabrication method 100. In thefabrication method 100, at first, a step 110 is performed for providinga color filter substrate. In this embodiment, the step 110 for providingthe color filter substrate includes step 112 for providing a substrate,step 114 for forming a sensing matrix, step 116 for forming colorfilters and step 118 for forming a common electrode. In the followingdescriptions, the step 110 for providing the color filter substrate isdescribed in detail.

In the step 110 for providing the color filter substrate, at first, thestep 112 is performed to provide a glass substrate 210, as shown in FIG.2a . The glass substrate 210 has a first surface 212 and a secondsurface 214, wherein the first surface 212 is opposite to the secondsurface 214.

Then, the step 114 for forming a sensing matrix is performed to form asensing matrix 220 on the first surface 212 of the glass substrate 210at a predetermined baking temperature, as shown in FIG. 2b . In thisembodiment, the predetermined baking temperature is greater than 230°C., and a sputter technology is used to form the sensing matrix 220 onthe glass substrate 210. However, embodiments of the present inventionare not limited thereto. In addition, the sensing layer 220 is formedfrom indium tin oxide (ITO) and the sensing layer 220 has a thicknessranging from 600 Angstrom to 1400 Angstrom. The step 114 is performedfor forming the sensing matrix 220 having a sheet resistance smallerthan or equal to 30 ohm/square, thereby decreasing the power needed by atouch-sensing circuit for touch-sensing operation. In this embodiment,the pattern of the sensing matrix 220 id formed by using aphotolithography process, and the sensing matrix 220 has perpendicularITO lines L, as shown in FIG. 5. However, the shape of the pattern ofthe sensing matrix 220 is not limited thereto.

It is noted that the touch-sensing panel of this embodiment isfabricated by using On Cell technology, and thus only one mask is neededin the step 114 for forming the pattern of the sensing matrix 220.

After, the step 114 for forming the sensing matrix, the steps 116 and118 are sequentially performed to form color filters 230 and a commonelectrode COM on the second surface 214 to obtain a color filtersubstrate P, as shown in FIG. 2c . The color filters 230 include colorresistors 232 and black matrixes 234. In this embodiment, the colorresistors 232 include red resistors, blue resistors and green resistors,but embodiments of the present invention are not limited thereto. Thecommon electrode COM is formed on the color filters 230, and thus thecolor filters 230 are disposed between the glass substrate 210 and thecommon electrode COM.

After the step 110 for providing the color filter substrate, a step 120is performed for providing a transistor substrate 240, as shown in FIG.2d . The transistor substrate 240 includes a glass substrate 242 and apixel layer 244. The pixel layer 244 is formed on the glass substrate242 and includes pixel units (not illustrated). Each of the pixel unitsincludes switching transistors and a pixel electrode to sequentiallyreceive image data signals to control alignment of liquid crystalmolecules in a liquid crystal layer.

After the step 120 for providing the transistor substrate 240, a step130 is performed to combine the transistor substrate 240 with the colorfilter substrate P and to dispose the liquid crystal layer LC betweenthe transistor substrate 240 and the color filter substrate P to obtaina touch-sensing liquid crystal panel 200, as shown in FIG. 2e , whereinthe common electrode COM of the touch-sensing liquid crystal panel 200is located between the liquid crystal layer LC and the color filters230. In this embodiment, the combination of the transistor substrate 240and the color filter substrate P are performed by using a sealant, butembodiments of the present invention are not limited thereto.

After the step 130 for combining the transistor substrate 240 with thecolor filter substrate P, a slimming step 140 is performed to slim thetouch-sensing liquid crystal panel 200, as shown in FIG. 2f . In thisembodiment, the slimming step 140 is performed on the glass substrate242 of the transistor substrate 240 to reduce the thickness of the glasssubstrate 242 from 0.4 mm to 0.2 mm. In other words, the thickness ofthe glass substrate 242 is reduced 50%.

It can be understood from the above descriptions that the fabricationmethod 100 of the touch-sensing liquid crystal panel uses the step 114to provide the sensing matrix 220 having a sheet resistance smaller thanor equal to 30 ohm/square to decrease the power needed by atouch-sensing circuit for touch-sensing operation. In addition, thefabrication method 100 of the touch-sensing liquid crystal panelincludes a slimming process to provide the thin and light touch-sensingliquid crystal panel 200.

Referring to FIG. 3, FIG. 3 is a flow chart showing a fabrication method300 of a touch-sensing liquid crystal panel in accordance with anotherembodiment of the present invention. The fabrication method 300 issimilar to the fabrication method 100, but the difference is in that thefabrication method 300 further includes encapsulating steps 312 and 320.

The encapsulating step 312 in a step 310 for providing a color filtersubstrate is performed between the steps 114 and 116. The encapsulatingstep 312 is performed before the step 116 to form an encapsulation layer410 on the sensing matrix 220, as shown in FIG. 4a . The encapsulationlayer 410 is used to protect the sensing matrix 220 to prevent sensingmatrix 220 from being damaged during following processes. In thisembodiment, the encapsulation layer 410 is formed by using a peelablesealant, but embodiments of the present invention are not limitedthereto.

The encapsulating step 320 is performed between the combination step 130and the slimming step 140. The encapsulating step 320 is performedbefore the slimming step 140 to form an encapsulation layer 420 on sidesurfaces of the touch-sensing liquid crystal panel to protect the sidesurfaces of the touch-sensing liquid crystal panel, as shown in FIG. 4b. The encapsulation layer 420 is used to protect the side surfaces ofthe touch-sensing liquid crystal panel to prevent the side surfaces ofthe touch-sensing liquid crystal panel from being damaged duringfollowing processes. The encapsulation layer 420 is formed by using apeelable sealant, but embodiments of the present invention are notlimited thereto.

It can be understood from the above descriptions that the fabricationmethod 300 of the touch-sensing liquid crystal panel uses theencapsulating steps 312 and 320 to form the encapsulation layers 410 and420 to prevent the side surfaces of the touch-sensing liquid crystalpanel from being damaged by the slimming step 140. The fabricationmethod 300 of the touch-sensing liquid crystal panel not only simplifiesthe production process of the touch-sensing liquid crystal panel butalso follows design standards of thin-film transistors, so as to providea more reliable touch-sensing liquid crystal panel.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentinvention without departing from the scope or spirit of the invention.In view of the foregoing, it is intended that the present inventioncover modifications and variations of this invention provided they fallwithin the scope of the following claims and their equivalents.

What is claimed is:
 1. A touch-sensing liquid crystal panel, comprising:a color filter substrate, comprising: a first glass substrate having afirst surface and a second surface, wherein the first surface isopposite to the second surface; a sensing matrix disposed on the firstsurface of the first glass substrate, wherein the sensing matrix isformed from indium tin oxide (ITO), and the sensing matrix has a sheetresistance smaller than or equal to 30 ohm/square; a plurality of colorfilters disposed on the second surface of the first glass substrate; anda transistor substrate, comprising: a second glass substrate having athickness smaller than or equal to 0.2 mm; and a pixel layer disposed onthe second glass substrate, wherein the pixel layer comprises aplurality of pixel units, and each of the pixel units comprises aswitching transistor and a pixel electrode; and a liquid crystal layerdisposed between the color filter substrate and the transistorsubstrate.
 2. The touch-sensing liquid crystal panel of claim 1, whereinthe sensing matrix has a thickness ranging from 600 Angstroms to 1400Angstroms.
 3. The touch-sensing liquid crystal panel of claim 1, whereinthe sensing matrix is formed by a baking operation at a bakingtemperature greater than 230° C.
 4. The touch-sensing liquid crystalpanel of claim 1, further comprises an encapsulation layer located onthe sensing matrix for protecting the sensing matrix.
 5. Thetouch-sensing liquid crystal panel of claim 1, further comprises anencapsulation layer located on a plurality of side surfaces of the colorfilter substrate and the transistor substrate for protecting the sidesurfaces.
 6. The touch-sensing liquid crystal panel of claim 1, whereinthe sensing matrix has a pattern of lines crossing each other.
 7. Atouch-sensing liquid crystal panel, comprising: a color filtersubstrate, comprising: a first glass substrate having a first surfaceand a second surface, wherein the first surface is opposite to thesecond surface; a sensing matrix disposed on the first surface of thefirst glass substrate, wherein the sensing matrix is formed from indiumtin oxide (ITO), and the sensing matrix has a sheet resistance smallerthan or equal to 30 ohm/square; a plurality of color filters disposed onthe second surface of the first glass substrate; and a transistorsubstrate, comprising: a second glass substrate treated by a slimmingprocess; and a pixel layer disposed on the second glass substrate,wherein the pixel layer comprises a plurality of pixel units, and eachof the pixel units comprises a switching transistor and a pixelelectrode; and a liquid crystal layer disposed between the color filtersubstrate and the transistor substrate.
 8. The touch-sensing liquidcrystal panel of claim 7, wherein the sensing matrix has a thicknessranging from 600 Angstroms to 1400 Angstroms.
 9. The touch-sensingliquid crystal panel of claim 7, wherein the sensing matrix is formed bya baking operation at a baking temperature greater than 230° C.
 10. Thetouch-sensing liquid crystal panel of claim 7, further comprises anencapsulation layer located on the sensing matrix for protecting thesensing matrix.
 11. The touch-sensing liquid crystal panel of claim 7,further comprises an encapsulation layer located on a plurality of sidesurfaces of the color filter substrate and the transistor substrate forprotecting the side surfaces.
 12. The touch-sensing liquid crystal panelof claim 7, wherein the sensing matrix has a pattern of lines crossingeach other.
 13. A touch-sensing liquid crystal panel, comprising: acolor filter substrate, comprising: a first glass substrate having afirst surface and a second surface, wherein the first surface isopposite to the second surface; a sensing matrix disposed on the firstsurface of the first glass substrate, wherein the sensing matrix isformed from indium tin oxide (ITO), and the sensing matrix has a sheetresistance smaller than or equal to 30 ohm/square; a plurality of colorfilters disposed on the second surface of the first glass substrate; anda transistor substrate, comprising: a second glass substrate; and apixel layer disposed on the second glass substrate, wherein the pixellayer comprises a plurality of pixel units, and each of the pixel unitscomprises a switching transistor and a pixel electrode; and a liquidcrystal layer disposed between the color filter substrate and thetransistor substrate.
 14. The touch-sensing liquid crystal panel ofclaim 13, wherein the sensing matrix has a thickness ranging from 600Angstroms to 1400 Angstroms.
 15. The touch-sensing liquid crystal panelof claim 13, wherein the sensing matrix is formed by a baking operationat a baking temperature greater than 230° C.
 16. The touch-sensingliquid crystal panel of claim 13, further comprises an encapsulationlayer located on the sensing matrix for protecting the sensing matrix.17. The touch-sensing liquid crystal panel of claim 13, furthercomprises an encapsulation layer located on a plurality of side surfacesof the color filter substrate and the transistor substrate forprotecting the side surfaces.
 18. The touch-sensing liquid crystal panelof claim 13, wherein the sensing matrix has a pattern of lines crossingeach other.